SEMPLE, George. A Treatise on Building in Water: in two parts : Part I. Particularly relative to the Repair and
Rebuilding of Essex-Bridge, Dublin; and Bridge-building in general; with Plans properly suited to the Re-building of
Ormond-Bridge. Part II. Concerning an Attempt to contrive and introduce quick and cheap Methods for erecting
substantial Stone Buildings and other Works, in Fresh and Salt Water, Quaking Bogs or Morasses, for various
Purposes; fully laid down, and clearly demonstrated, by Twelve Practical Propositions, but not in any Case
exceeding Ten Fathom deep: Together with a Plan for a spacious and commodious Harbour for the Downs in
England, projecting to Twenty Feet deep at low Water. To which is added Part III. Hibernia’s Free Trade; or, A Plan
for the general Improvement of Ireland; peculiarly adapted for Improving the Commercial and Landed Interest of
Ireland; and briefly demonstrating, that not only Great Britain, but the whole British Empire, may gain
proportionable Advantages thereby. The second edition. Illustrated with sixty-four copper-plates. London: Printed
for the Author: and Sold by T. Longman, No. 39, Paternoster-row; J. Almon, No. 178, Piccadilly; and I. Taylor, No.
56, opposite Great Turnstile, Holborn, 1780. Quarto. pp. x, , 190, 64 (plates). Contemporary half calf over marbled boards, title and author in gilt on green morocco labels. Armorial bookplate of the Royal Engineer
Establishment Library, Chatham on front pastedown. Spine professionally rebacked with wear to corners, some mild
foxing. Marginal annotations in pencil. A very good copy. Very scarce.
George Semple (1700-1781), architect, engineer and master-builder was the most distinguished member of
a family who were for centuries builders in Dublin. They are to be found in the Guild of Plasterers,
Carpenters and Masons from before 1744. Jonathan Swift in his will left money for the building of a
hospital for the insane, St. Patrick’s Hospital usually called Swift’s Hospital was built on land donated by
the directors of Dr. Steevens’s and adjacent to it.
“He left the little wealth he had,
To build a house for fools and mad,
And showed by one satiric touch,
No nation wanted it so much”.
The architect for this project was George Semple. He had another connection with Swift, his earliest known
work is the granite steeple of 100 feet in St. Patrick’s Cathedral, which he designed and erected in 1749.
Swift as far back as 1714, by obstruction and procrastination, prevented Archbishop King from adding such
a spire in ‘brick’. He must therefore have known Semple and approved of his work. George built houses in
Dublin and at least one country mansion. His magnum opus was the rebuilding of Essex Bridge. The
present bridge is the third on the site, the first was built in 1676, by Humphrey Jervis, Lord Mayor of
Dublin, from stones obtained from the ruins of St. Mary’s Abbey. This structure had many faults and was
frequently damaged by floods. A major failure of part of two spans occurred in 1751, and Semple repaired
the old bridge within ten days for the sum of one hundred guineas. So successful was his repair that he was
given the contract to rebuild the whole bridge. In 1753 he began demolition of the existing structure. He
travelled to London where he bought £40 worth of books on engineering matters. He was however very
disappointed on his return to Dublin, realising that these books were virtually useless: “I cannot describe the
indignation and sorrow I felt at finding an art of such public utility as that of building bridges confessedly is
so shamefully neglected. Eventually he managed to acquire a copy of ‘Architecture Hydraulique’ by
Belidore, although in French, which he could not read, the plans were sufficient for his purpose”. Its design
was based on the magnificent Westminster Bridge, and it had five semicircular arches. Semple preferred to
build timber cofferdams, which were pumped dry, thus enabling in-situ construction to proceed below water
level. On 10 April 1755 “the (new) Bridge was left open for the use of the Public in general”, at a cost
£20,661 and was completed in two years and eight days. Zozimus (Michael Moran), the blind balladeer,
often took his stand on the bridge. Unfortunately the city planners replaced Semple’s bridge in 1873, with
what is now called Grattan Bridge. The lack of reference books on bridge building prompted Semple to
undertake the present work. It is a pioneering study, and surely, is one of the most adventurous classics of
engineering technical writing, in which the author gives a very full and vivid description of the rebuilding
of Essex Bridge.